The last time I used Sigmafine, the Model Analyses plugin worked without any issues, and no special registration was required. I would ask which version of PSE are you using - the 32-bit legacy version, or the 64 bit version? Which PIPC directory did you put the Sigmafine plugin DLL into - C:\Program Files\PIPC (64-bit program location), or C:\Program Files (x86)\PIPC (32-bit program location)?

I suspect that bitness version may be the issue here. In the absence of any specific installation instructions from Pimsoft, I would also suggest trying the DLL in both locations mentioned above, and the opening the corresponding version of PSE.

What version of AF Client do you have installed and what is the version of the AFPlugInAnalyses.dll that you are attempting to use (right-click on the assembly and check the version on the Details tab)? Also, check that it has a Digital Signatures tab and is signed with an OSIsoft certificate.

The version of the AFPlugInAnalyses.dll and AF Client should be the same version to ensure compatibility. You should contact Pimsoft and see if they will provide you with a later version of the Model Analysis plugin.

Unfortunately the documentation on PSE plugins is not publicly available as far as i know, so the only help you could get here is from OSI staff. But as this is an add-on from pimsoft, i would say contact them to provide support.